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// Copyright (C) 2019 T. Zachary Laine
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#include <boost/stl_interfaces/iterator_interface.hpp>
#include <string>
#include <cassert>
//[ repeated_chars_iterator
struct repeated_chars_iterator : boost::stl_interfaces::iterator_interface<
#if !BOOST_STL_INTERFACES_USE_DEDUCED_THIS
repeated_chars_iterator,
#endif
std::random_access_iterator_tag,
char,
char>
{
constexpr repeated_chars_iterator() noexcept :
first_(nullptr),
size_(0),
n_(0)
{}
constexpr repeated_chars_iterator(
char const * first, difference_type size, difference_type n) noexcept :
first_(first),
size_(size),
n_(n)
{}
constexpr char operator*() const noexcept { return first_[n_ % size_]; }
constexpr repeated_chars_iterator & operator+=(std::ptrdiff_t i) noexcept
{
n_ += i;
return *this;
}
constexpr auto operator-(repeated_chars_iterator other) const noexcept
{
return n_ - other.n_;
}
private:
char const * first_;
difference_type size_;
difference_type n_;
};
//]
int main()
{
//[ repeated_chars_iterator_usage
repeated_chars_iterator first("foo", 3, 0); // 3 is the length of "foo", 0 is this iterator's position.
repeated_chars_iterator last("foo", 3, 7); // Same as above, but now the iterator's position is 7.
std::string result;
std::copy(first, last, std::back_inserter(result));
assert(result == "foofoof");
//]
}
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